Recently, sensor-equipped display devices comprising sensors (often called touch panels) which detect contact or approach of an object, have been put into practical use. As an example of the sensor, a capacitive sensor capable of detecting contact or approach of a conductor such as a finger, based on a variation in electrostatic capacitance is well known. A detection electrode and a sensor driving electrode constituting the sensor are disposed in a display area in which images are displayed, and opposed to each other with a dielectric interposed between the electrodes.